At 48 people have been injured in an explosion near the ruling AKP party's headquarters in the city of Van in southeastern Turkey.
Turkish news agency Dogan has quoted local police who said initial reports suggest it was a car bomb.
The blast hit some 200 metres from the Van provincial governor's office and ripped through the city's central district setting buildings and cars alight.
It ripped the front from a four-storey building but the business district, which is normally busy at that time on a Monday morning, was unusually quiet as it was the first day of the Muslim holiday Eid al-Adha.
Local television footage showed smoke billowing from a building and firefighters battling flames.
There have been no immediate reports of any deaths but two are said to be in critical condition in hospital.
The blast was near to the provincial headquarters of President Recep Tayyip Erdogan's Justice and Development Party (AKP) and the local AKP party's deputy leader, Burhan Kayatürk, told CNN Turk that the target of the attack was their regional headquarters but the building was well-secured and had not been badly damaged.
Van province's population is mostly Kurdish. Separatists groups such as the Kurdistan Workers' Party (PKK) have carried out several terror attacks on the country in recent months after a two-year ceasefire with the government broke down last year.
They have been waging a three decades-long insurgency for Kurdish autonomy in the south-east of the country which has killed an estimated 40,000 people.
Security sources have blamed the PKK for the attack but there has been no immediate claim of responsibility.
Development Minister Lutfi Elvan condemned the attack, the perpetrators had no respect for the holiday.
He told the Andolu agency: "Of course the necessary response is being given to these traitors, and will continue being given.
"Our nation and our state are strong. we are easily overcoming them and God willing we will root out this divisive terrorist organization as well as Daesh (Isis). We don't want even a single person remaining."
The attack came a day after Mr Erdogan removed two dozen mayors from Kurdish-run municipalities from office in four towns in the wider Van province over alleged links to the PKK - which is treated as a terrorist organsation in Turkey.
The removals triggered protests and the pro-Kurdish opposition party, the Peoples' Democratic Party (HDP), saying the move was an illegal "administrative coup".
The country is also being racked by an insurgency led by Isis militants angry at the country's strikes against them over the border in Syria.
In June, 41 people were killed and 239 others were wounded when two suicide bombers detonated explosives before three others opened fire with AK-47s at Istanbul Airport.
Turkey has seen widespread political upheaval since an ill-fated attempt to oust Mr Erdogan by some members of the army on 15th July.
Since the attempted coup Mr Erdogan has staged a widespread crackdown on the "Gullenists" - supporters of the exiled Muslim cleric Fethullah Gulen - which has seen the arrest of at least 26,000 people with thousands more being sacked or forced to resign from government posts, the Armed Forces and the police.
Additional reporting by Reuters
Register for free to continue reading
Registration is a free and easy way to support our truly independent journalism
By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists
Already have an account? sign in
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies